ES2212332T3 - TURBULIZERS WITH INTERRUPTED CORRUGATIONS FOR THERMOINTERCHANGERS. - Google Patents

Abstract

A heat exchanger (10) is disclosed of the type having stacked plate pairs or tubes (12) defining flow passages, with turbulizer (18, 30, 45, 50, 55, 60) located inside such flow passages. The turbulizers (18, 30, 45, 50, 55, 60) are of the expanded metal type having rows of convolutions (32, 34). The convolutions (32, 34) are interrupted periodically to form non-convoluted pressure recovery zones (40) located between or downstream of the convolutions (32, 34). Also, the rows of convolutions (32, 34) can be spaced apart to provide longitudinal neutral zones (56, 61) between the rows of convolutions. The pressure recovery zones (40, 56, 61) and longitudinal neutral channels (62) reduce pressure drop in the heat exchanger (10) without appreciably reducing heat transfer.

Description

Turbulizers with interrupted corrugations for heat exchangers.

The present invention refers to heat exchangers and, to turbulizers used in heat exchangers

In heat exchangers made with multiple tubes or pairs of stacked plates, which define steps of flow between them, the use of turbulizers located in the tubes, or between the plates, within each pair of plates, to reinforce thermal transfer, especially when, through These flow steps, a liquid flows, such as oil. These turbulizers usually have the form of inserts of expanded metal, and have undulations or corrugations formed in them, to create turbulence in the flow and, in this way, increase, the heat transfer of the heat exchanger.

Although conventional turbulizers increase certainly thermal transfer, a difficulty that found in this type of turbulizers is that they increase equally resistance to flow or pressure drop within the heat exchanger In fact, the flow resistance still increases more than the thermal transfer gain produced by the turbulizer, because only part of the increase in turbulence caused by the turbulizer is effective to promote the thermal transfer The rest is lost in parasitic flows or inefficient whirlpools.

An attempt to relieve the pressure drop Increased mentioned above has been described in the Patent EP-A- 203458, which describes turbulizers for heat exchangers having the characteristics of the preamble of The attached Claim 1: a difficulty with the turbulizers described in this patent is that the undulating areas of the turbilizers are too large with respect to the rows of undulations, so that the transfer efficiency of Heat is too low.

The object of the present invention is that of improve the balance between heat exchange efficiency and the resistance to the fluid with respect to the turbulizers known.

In accordance with the present invention, it is supplied a turbo exchanger for heat exchangers, the turbulizer comprising a flat member having a plurality of longitudinal parallel rows of undulations formed therein characterized because said undulations are interrupted to form longitudinal neutral channels only between some of the adjacent rows of undulations.

In this way, the undulations are interrupted periodically in the turbulizer to form neutral channels not corrugated located between the groups of longitudinal rows adjacent undulations. Surprisingly, this reduces substantially the pressure drop caused by the turbulizer without significantly decreasing thermal transfer.

According to another aspect of the invention, in she is provided a heat exchanger comprising a plurality of spaced apart spaced apart members fluid passages between them; defining said tube members openings spaced separately in and out; and a turbulizer as previously defined and located at least one of the fluid passages between the respective openings of input and output.

Preferred embodiments of the invention will be now described, by way of example, with reference to the attachments drawings, in which:

Figure 1 is a perspective view exploded from a preferred embodiment of a heat exchanger type of plate according to the present invention;

Figure 2 is an enlarged perspective view of a portion of a turbulizer usable in the heat exchanger of Figure 1, according to the technique previous;

Figure 3 is an elevation view of a portion of the turbulizer of Figure 2 taken in the direction of the arrow 3 in Figure 2;

Figure 4 is a plan view of the turbulizer of Figures 2 and 3;

Figure 5 is a perspective view of a turbulizer according to the present invention;

Figure 6 is an elevation view of a portion of the turbulizer of Figure 5 taken in the direction of the arrow 6 in Figure 5;

Figure 7 is a plan view of the turbulizer shown in Figures 5 and 6;

Figure 8, is a perspective view of another realization of a turbulizer in accordance with the present invention,

Figure 9 is an elevation view of a portion of the turbulizer of Figure 8.

Figure 10 is a plan view of the turbulizer shown in Figures 8 and 9;

With reference to Figure 1, an embodiment Preferred heat exchanger according to the present invention is generally indicated by numerical reference (10) The heat exchanger (10) is formed by a plurality of tubular members or pairs of plates (12), spaced apart, each of which has a top plate (14), a plate bottom (16) and a turbulizer (18) located between them. Plates (14), (16) are arranged in an attached position and have edges attached peripherals (20) .The plates (14), (16) also have some raised central portions (22), which define a flow passage between them, where the turbulizers are located (18). The raised central portions (22) also define separate openings (24), (26) inlet and outlet, for flow of the fluid, such as oil, through the pairs of plates. When the heat exchanger is mounted, all openings input (24) are aligned and in communication, forming an entry or admission set, and all exit openings (26) are aligned and in communication, forming a head output Between the pairs of plates are located some expanded metal fins (28) to allow other fluid, by example air, can pass transversely through the pairs of plates. The plates (14), (16) that are in contact with the fins (28) are separated by raised end flanges (29) to leave room for the fins (28) between the portions central (22) of the plates.

The plates (14), (16) and the fins (28) can have any desired shape and configuration and, per se, I don't know considered part of the present invention. In fact the plates (14), (16) can be formed with embossed outwards, and that match in pairs of adjacent plates, in which case, they are not they would use the fins (28).

Referring below to the Figures 2, 3, and 4, a turbulizer (30) is shown that it could be used as the turbulizer (18) in Figure 1, according to a prior art solution and which is not comprised of the attached claims.

Figures 5 and 8 show other embodiments Preferred turbulizers according to the present invention. Any of them could be used as a turbulizer (18) in the heat exchanger (10) shown in Figure 1. The turbulizers shown in Figures 2.5, and 8 are nothing more than illustrations of sections or parts of the turbulizers. It will be noted that these turbulizers can be made of any length or width desired, depending on the manufacturing procedure. The Turbulizers are usually stamped or laminated with aluminum approximately 0.01 inches (0.25 mm) thick. However, other materials can also be used for turbulizers or thicker or thinner materials.

The turbulizer (30) is a flat member that It has a series of undulations (32), (34) formed in the miso. The undulations (32), (34) are arranged in parallel rows. When the turbulizer (30) has an elongated shape, the undulations (32), (34) are arranged in parallel and longitudinal rows (36), as well as in parallel transverse rows (38).

The undulations (32), (34) are interrupted periodically to form pressure recovery zones (40) not undulating, located between undulations (32), (34) or in the course bottom of undulations (32), (34), in each row of undulations (36). In other words, the undulations (32), (34) of each row are separated by pressure recovery zones (40) instead of being located next to each other.

The turbulizer (30) has a central plane that it contains pressure recovery zones (40), as indicated by the arrow (41) of figure 3, and undulations (32) (34) that are alternately extend above (undulations (32)) and by below (undulations (34)) of the central plane (41). Ripples (32), (34) have the form of bridges, and the turbulizer (30) has a high pressure drop orientation in the direction of the bridges, or in the longitudinal direction, and a drop orientation to low pressure in the direction that passes under the bridges or in cross direction. In the embodiment illustrated in Figure 2, the undulations (32) (34) are interrupted in the high pressure drop direction by zones (40) of the pressure recovery, located between the undulations or in the lower course of them. As best seen in Figure 4, the pressure recovery zones (40) are located, by their part, in transverse zones or neutral channels (41).

When the turbulizer (30) is used as the turbulizer (18) in the heat exchanger (10) of Figure 1, the fluid flows in high pressure drop direction or direction parallel to the longitudinal rows (36) from the openings of inlet (24) to the outlet openings (26). Fluid flows around, under or through undulations (32), (34). This produces turbulence and reduces the growth of the boundary layer, increasing the coefficient of thermal transfer. However the recovery zones (40) allow pressure recovery to in order to reduce resistance to flow or pressure drop in the fluid that passes from the inlet openings to the openings of exit (26).

In the turbulizer (30), the undulations (32), (34) are aligned in the direction of low drop pressure or transverse direction. Moreover, the zones (40) of pressure recovery are aligned in the direction of the low pressure or transverse direction drop, to form neutral channels (41). Pressure recovery zones (40) thus form continuous neutral channels (41) in the direction of The low pressure drop. These neutral channels (41) provide also areas that can be used to eject the turbulizer from the dies used to make the turbulizer.

The width of the wavy longitudinal rows (36) is preferably as narrow as possible for the tool design and for maintenance purposes. For purposes of car cooling, a preferred minimum width would be approximately 0.02 inches (0.5 mm). The maximum width does not It should exceed ten times the minimum. The maximum width would be typically about 0.2 inches (5 mm). The length of the longitudinal zones (40) of the pressure recovery varies of the separation longitudinally in approximately 5% of the longitudinal separation or between centers of line separation central between undulations (32). (34) up to 75% approximately of the separation between two consecutive undulations any (32), (34). A preferable scale would be between 0.02 inches (0.5 mm) to 0.5 inches (1.25 cm) approximately, or from about 40% to 50% of the center line of the distance between central lines, of longitudinally undulations consecutive (32), (34).

The height of the undulations (32), (34) by above or below the central plane (41) containing areas of pressure recovery (40) depends on the thickness of the material used for the turbulizer (30). This height should not be less than the thickness of the material and typically varies from the minimum at about 10 times the thickness of the material, in which use aluminum for the turbulizer (30). A good scale would be from 0.01 inches (0.25 mm) to 0.5 inches (1.25 cm).

The length of the undulations (32), (34) is normally, and longitudinally, about 2 times the height of the undulations. The height normally varies from about 2 times the thickness of the material up to about 20 times the thickness of it. A good scale would be 0.02 inches (0.5 mm) to 1.0 inch (2.5 cm) approximately.

Referring immediately to the figures 5,6 and 7, a turbulizer (55) is illustrated which is mostly similar to the turbulizer (30) of Figure 2, except for the undulations (32), (34) that are equally interrupted in the direction of the low pressure drop, to form zones additional (56) pressure recovery, located between some of the rows of undulations (36). Actually the area pressure recovery extends longitudinally to all along the turbulizer (55), to form longitudinal channels neutral (58) in the direction of high-pressure or longitudinal drop of the turbulizer (55). For manufacturing purposes, it is preferred that the width of the neutral channels (58) is approximately the same as the width of the undulation rows (36). In the turbulizer (55), the undulations (32), (34) are aligned in the low pressure or transverse drop direction, but could be also staggered. When the undulations (32), (34) are aligned in the direction of low pressure or transverse fall, it understand that the pressure recovery zones (40) are aligned to provide transverse neutral channels (59) in the low pressure drop direction, and recovery zones (56) pressure are aligned to provide neutral channels Longitudinal (58) in the direction of high pressure drop. When the undulations (32), (34) are staggered, they would only form longitudinal neutral channels (58). In all other aspects, the turbulizer (55) is similar to the turbulizers (30), (45) and (fifty).

Referring below to the figures 8, 9 and 10, a turbulizer (60) is illustrated in which the undulations (32), (34) are only interrupted in the direction of low pressure or transverse drop, and only among some of the rows of undulations (36). These interruptions have some pressure recovery zones (61) in the form of neutral channels Longitudinal (62). In all other aspects, the turbulizer (60) is similar to turbulizers (30) and (55). In figures 8 a 10, the turbulizer (60) is shown cut in the direction longitudinal, in the middle of the undulations (32), (34). In the practice, the turbilizers would normally be cut in the longitudinal direction between undulations, as in the case of Figures 1 to 7.

Once described the preferred embodiments of the invention, it will be understood that various can be introduced modifications to the structures described above. For example in instead of using pairs of plates (12) as tubular members that define the flow steps that contain the turbulizers (18) Continuous, flat or oblong tubes could be used. In this case, the turbulizers (18) would be inserted longitudinally in a end of the tubes. In the turbulizers (18), the undulations (32), (34) have been illustrated rounded with various curvatures. These undulations can have any configuration, for example semicircular, sinusoidal, trapezoidal or even V-shaped, if want. In the heat exchanger (10) illustrated in Figure 1, the turbulizer (18) is shown oriented so that the flow continues the direction of fall at low pressure, or longitudinal direction. Do not However, the turbulizer could be turned 90 degrees, so that the flow from the entrance (24) to the exit (26) follow the low pressure drop direction, if desired. It will be understood also that the various characteristics of the turbulizers (30), (55) and (60) and be matched, or use a combination of these characteristics in it turbulizer On the other hand any given heat exchanger could have a combination of the turbulizer classes above described. Other modifications to the structure described previously they will be apparent to those experts in the technique.

Claims (10)

1. A turbulizer for a heat exchanger having the turbulizer a flat member having a plurality of parallel rows of undulations (36) of undulations (32, 34) formed therein characterized in that said undulations (32 34) are interrupted to form channels Longitudinal neutrals (58; 62) only between some of the adjacent longitudinal rows (36) of the undulations. 2. A turbulizer according to Claim 1, characterized in that the undulations (32, 34) are in the form of bridges, the bridges being longitudinally oriented to define an orientation towards the high pressure drop in the direction of the bridges and an orientation towards the low pressure drop transversely in the direction that passes under the bridges. 3. A turbulizer according to Claim 2, characterized in that the rows (36) of the corrugations are interrupted in the longitudinal direction to form pressure recovery zones (40) located longitudinally between the corrugations (32,34). 4. A turbulizer according to Claim 3, characterized in that the undulations (32, 34) are aligned in the transverse direction, the pressure recovery zones (40) also being aligned transversely to form neutral channels (59) in the cross direction. 5. A turbulizer according to Claim 2, characterized in that the undulations (32, 34) are staggered in the transverse direction. 6. A turbulizer according to claim 2, characterized in that the undulations (32,34) are aligned in the transverse direction. 7. A turbulizer according to Claim 3, characterized in that the turbulizer has a central plane containing the pressure recovery zones, and because the undulations (32, 34) in each row (36) of the undulations are alternately extended by above and below the central plane. 8. A turbulizer according to Claim 5, characterized in that it has a central plane containing the pressure recovery zones, and because the undulations (32, 34) in each row (26) of the undulations alternately extend above and above under the central plane. 9. A turbulizer according to Claim 1, characterized in that said groups include three rows (36) of undulations, a single longitudinal neutral channel (58; 62) being between each of the groups. 10. A heat exchanger (10) comprising a series of separate tubular members, which define steps between them of flow, said tubular members defining separate openings entry and exit (24, 26); and a turbulizer (55; 60) according with any one of the preceding claims, being located said turbulizer (55; 60) in at least one of the steps of flow between the corresponding inlet and outlet openings (24, 26).